Laser center dependent exposure strategy

Abstract

Disclosed is a method for controlling an energy input device of an additive manufacturing device. A beam bundle deflection center is assigned to each of the number of beam bundles from which this beam bundle is directed onto the build plane. Each beam bundle deflection center is assigned a projection center corresponding to a perpendicular projection of the position of the beam bundle deflection center onto the build plane. The directions of the movement vectors of the number of beam bundles when scanning the trajectories are defined such that at each of the solidification points in this section the movement vector has an angle with respect to a connection vector from this solidification point to the projection center of the beam bundle used, which angle is smaller than a predetermined maximum angle γ1.

The invention claimed is: 
     
         1 . A method for controlling an energy input device of an additive manufacturing device for manufacturing a three-dimensional object, the method comprising:
 applying a building material layer upon layer using the additive manufacturing device; and   solidifying the building material in a build plane using the energy input device by supplying radiant energy to solidification points in each layer by scanning a cross-section of the three-dimensional object with a number of beam bundles provided by the energy input device along a plurality of trajectories in the build plane, wherein at least one section of the cross-section is solidified, sub-area by sub-area, wherein each of the number of beam bundles is assigned a beam bundle deflection center above the build plane, the beam bundle deflection center defining a location from which the beam bundle is directed onto the build plane, each beam bundle deflection center being assigned a projection center that corresponds to a perpendicular projection of a position of the beam bundle deflection center onto the build plane;   defining an order of scanning of the trajectories in at least one of the sub-areas having solidification points scanned with a beam bundle assigned to the respective sub-area, wherein the defined order allows for the respective beam bundle to scan trajectories that are located closer to the projection center of the beam bundle before trajectories that are located further away from the projection center, and   defining a chronological order of scanning of sub-areas having the solidification points scanned with beam bundles assigned to the sub-areas, wherein the defined chronological order allows for the beam bundle to scan sub-areas that are located closer to the projection center of the beam bundle before sub-areas that are located further away from the projection center.   
     
     
         2 . The method of  claim 1 , wherein in a sub-area in which the trajectories run substantially parallel to one another and the trajectories are scanned in the defined order, a movement vector of at least one solidification point has an angle with respect to a connection vector from the solidification point to the projection center of the beam bundle used, wherein the angle is greater than a predetermined minimum angle. 
     
     
         3 . The method of  claim 1 , further comprising passing a gas flow across a respective solidification point during scanning; and
 selecting the beam bundle deflection center for which a directional component of the gas flow points from the solidification points to the projection center associated with the beam bundle deflection center for scanning the solidification points in the at least one of the sub-areas.   
     
     
         4 . A method for controlling an energy input device of an additive manufacturing device for manufacturing a three-dimensional object using the same,
 wherein the object is manufactured using the additive manufacturing device by applying a building material layer upon layer and solidifying the building material in a build plane using the energy input device by supplying radiant energy to solidification points in each layer which are assigned to the cross-section of the object in this layer, by scanning these solidification points with a number of beam bundles provided by the energy input device along a plurality of trajectories in the build plane,   each of the number of beam bundles being assigned a beam bundle deflection center above the build plane, from which the beam bundle is directed onto the build plane,   wherein each beam bundle deflection center is assigned a projection center that corresponds to a perpendicular projection of the position of the beam bundle deflection center onto the build plane,   wherein at least one section of an object cross-section is solidified, sub-area by sub-area, wherein the chronological order of scanning of sub-areas, whose solidification points are scanned with a beam bundle assigned to these sub-areas, is defined such that sub-areas that are located closer to the projection center of the beam bundle are scanned before sub-areas that are located further away from the projection center.   
     
     
         5 . The method according to  claim 4 , in which the section has a plurality of sub-areas that have a rectangular shape in a plan view of the build plane, the trajectories in the section being substantially parallel to one another and substantially parallel to the transverse sides of the sub-areas, wherein the length of a perpendicular from the projection center to a straight line running through a sub-area parallel to a long side is used as a measure for the distance of a sub-area from the projection center. 
     
     
         6 . The method according to  claim 4 , in which, during the manufacture of a three-dimensional object with the additive manufacturing device, a gas flow is passed across the respective solidification point during scanning,
 wherein, for the scanning of the solidification points in the at least one section of an object cross-section, a beam bundle deflection center is selected for which a directional component of the gas flow points from the solidification points to the projection center assigned to the beam bundle deflection center.   
     
     
         7 . The method of  claim 1 , wherein a beam bundle deflection angle exceeds a deflection minimum angle during scanning of the sub-area having at least one solidification point, wherein the beam bundle deflection angle is defined as an arctangent of a quotient of a distance of the solidification point from the projection center and a length of a projection line of the beam bundle deflection center, wherein the projection line of the beam bundle deflection center is-a perpendicular to the build plane that connects the projection center with the beam bundle deflection center. 
     
     
         8 . The method of  claim 1 , wherein a respective beam bundle is used for scanning the building material along a trajectory, wherein a beam bundle deflection angle does not exceed a predetermined deflection maximum angle, wherein the beam bundle deflection angle is defined as an arctangent of a quotient of a distance of a solidification point from the projection center and a length of a projection line of the beam bundle deflection center, wherein the projection line of the beam bundle deflection center is a perpendicular to the build plane that connects the projection center with the beam bundle deflection center. 
     
     
         9 . The method of  claim 1 , wherein different energy input parameter values are specified for a larger value of a beam bundle deflection angle than for a smaller value of the beam bundle deflection angle, wherein the beam bundle deflection angle is defined as an arctangent of a quotient of a distance of a solidification point from the projection center and a length of a projection line of the beam bundle deflection center, wherein the projection line of the beam bundle deflection center is perpendicular to the build plane that connects the projection center with the beam bundle deflection center. 
     
     
         10 . The method of  claim 8 , wherein a number of changes from one beam bundle to another beam bundle during scanning of the trajectories in the sub-area is limited to a maximum value. 
     
     
         11 . The method of  claim 10 , wherein the maximum value is defined as a function of specifications for a quality of the sub-area or a production time of the object. 
     
     
         12 . The method of  claim 1 , wherein the sub-area is at least a part of a bottom surface area of the cross-section, wherein the bottom surface area is defined in that no solidification of building material is specified in at least one of p layers below the bottom surface area, wherein p is a predetermined natural number, or wherein the sub-area is at least a part of a top surface area of the cross-section, wherein the top surface area is defined in that no solidification of building material is specified in at least one of q layers above the top surface area, wherein q is a predetermined natural number. 
     
     
         13 . The method of  claim 1 , wherein the sub-area is at least a part of a contour region of the cross-section. 
     
     
         14 . An additive manufacturing method for manufacturing a three-dimensional object, the method comprising:
 applying a building material layer upon layer using the additive manufacturing device; and   solidifying the building material in a build plane using an energy input device by supplying radiant energy to solidification points in each layer,   wherein the solidification points are assigned to the layer, by scanning a cross-section of the three-dimensional object with a number of beam bundles provided by the energy input device along a plurality of trajectories in the build plane,   wherein the energy input device is controlled by the method of  claim 1 .